Development and characterization of biodegradable hydroxyethyl cellulose/polyacrylic acid films loaded with pomegranate peel extract with antibacterial activity

From an academic standpoint, scientists all around the globe have been paying close attention to the use of inexpensive, naturally occurring polymers. Given this consideration, the research aimed to integrate hydroxyethyl cellulose (HEC) and polyacrylic acid (PA), to produce biodegradable films for food packaging. Different concentrations of pomegranate peel (PoP) extract were incorporated into the film solutions to augment the antimicrobial effectiveness of these films. As a result, four film products were obtained by incorporating four different concentrations (2, 4, 6, and 8 mL) of PoP extract into the HEC/PA film matrix. These films were coded as PoP-1@HEC/PA film, PoP-2@HEC/PA film, PoP-3@HEC/PA film, and PoP-4@HEC/PA film, which were compared to the film without PoP extract (HEC/PA film). The film products were characterized, and the data confirmed the deposition of PoP extract onto the surface of the HEC/PA film. The water contact angle of HEC/PA film was initially measured as 77.3 degrees, which decreased to 71.4 degrees with the addition of PoP extract (PoP-4@HEC/PA film). These values remained above the threshold of 20 degrees, indicating their suitability for food packaging and preservation. Furthermore, the water vapor transmission rate (WVTR) of PoP-4@HEC/PA film was lower compared to HEC/PA film. The surface area covered by the deposited PoP extract particles increased with the higher concentrations of the extract in the polymer films. Biodegradability evaluations demonstrated that PoP extract enhanced the degradation of the HEC and PA polymer films over time. Contact angle assessments also indicated the hydrophobic nature of the resulting films, with contact angles exceeding 60 degrees. Antimicrobial studies were conducted on the PoP extract against four different foodborne species. The results revealed strong microstatic effects of PoP extract against the targeted microbes. The susceptibility of various bacterial strains to PoP extracts varied, with the methanolic PoP extract producing inhibitory zones of 30.3, 25.3, 22.6, and 18 mm against Escherichia coli, Staphylococcus aureus, Candida albicans, and Aspergillus niger, respectively, in the disc diffusion assay. The antibacterial evaluation was further performed by incorporating different concentrations of PoP extract into the HEC/PA film. The results demonstrated that PoP-3@HEC/PA and PoP-4@HEC/PA films exhibited the highest inhibitory effects. Notably, complete reduction of bacteria was achieved after exposure to PoP-4@HEC/PA film. Based on the promising findings, the developed biodegradable films hold potential for eco-friendly food packaging, as they can extend the shelf life of packaged food products.